The present invention relates to components useful in integrated circuits and pertains particularly to resistor shapes for heating devices on an integrated circuit.
For some applications, heating devices are implemented on integrated circuits. For example, one type of total internal reflection (TIR) switching elements used in an optical cross-connection switch utilizes thermal activation to displace liquid from a gap at the intersection of a first optical waveguide and a second optical waveguide. See for example, U.S. Pat. No. 5,699,462. In this type of TIR, a trench is cut through a waveguide. The trench is filled with an index-matching liquid. A bubble is generated at the cross-point by heating the index matching liquid with a localized heater. The bubble must be removed from the crosspoint to switch the cross-point from the reflecting to the transmitting state and thus change the direction of the output optical signal. Efficient operation of such a TIR element requires effective placement and operation of heating devices within and around the TIR elements. Similarly, heating devices are used in other types of devices, for example, to eject ink from a printer head in an inkjet printer.